Toepiece Which Releases a Boot Automatically as a Result of Twisting

ABSTRACT

A toepiece of a binding to secure a boot to a gliding board includes two rigid jaws pivotable about respective horizontal axes oriented in a longitudinal direction. A releasing system for automatically releasing the boot by twisting the boot, associated with tilting of jaws. Tilting of at least one jaw causes the toepiece to take up a closed configuration, a releasing configuration for releasing the boot as a result of twisting of the boot, or a fitting configuration. The releasing system includes an elastic return for the jaws in the closed configuration and releasing configuration of the toepiece. Connection between a jaw and the elastic return includes at least one transmission link articulated to the jaw about a hinge axis oriented in the longitudinal direction so the jaw and transmission link form a knuckle joint that deforms in the plane corresponding to the transverse direction and vertical direction of the toepiece.

The invention relates to a toepiece of a binding device for securing a boot to a gliding board. This toepiece is particularly suitable for ski touring. It also relates to a binding device for securing a boot to a gliding board and to a gliding board as such equipped with such a device and/or such a toepiece.

The document EP-A1-2353673 describes a toepiece of a binding device for securing a boot to a touring ski. The front binding of the boot is based on two jaws of the toepiece that are articulated about longitudinal pivot axes with respect to a base of the toepiece that is intended to be fixed to the touring ski. Each jaw comprises retaining elements that are intended to engage with the touring ski boot. The two jaws articulated by way of a spring system in order to take up a first stable position, known as the closed position, in which the retaining elements engage with corresponding hollow parts formed laterally in the anterior part of the touring ski boot, in order to fix the boot, only allowing it to move in rotation about a transverse axis with respect to the ski, and a second stable position, known as the open position, in which the jaws are spaced apart such that the retaining elements free the boot, which can be separated from the touring ski. The binding of the front part of the boot to a touring ski equipped with such a toepiece is carried out by positioning the boot such that the two jaws take up the second, open position, then by pressing strongly with the heel of the boot on the spring-based system, thereby allowing the articulated jaws to move toward their first, closed position in which they move toward the boot in order to position the retaining elements within complementary hollow parts of the boot.

A drawback with such existing toepieces is their lack of safety in the case of the skier falling, in particular in the case of a twisting fall on the part of the skier in a downhill situation of the alpine skiing type, involving a twisting movement of the boot with respect to the ski, during which the boot remains trapped in the toepiece, thereby risking injury to the skier.

A known manner for automatically freeing the touring boot in order to prevent injury to the skier is to provide a heel piece which is intended to fix the rear part of the touring boot and is configured so as to be able to free the boot in the event of a fall, in particular as a result of twisting of the boot, but also as a result of a forward fall and/or a backward fall. However, such heel pieces are complex, resulting in higher costs and substantial weight, and are unable to comply with safety criteria dictated by the alpine standard ISO9462. This limits the performance of the touring ski for which the overall weight is currently an essential criterion.

The document WO2009/121187A1 describes a toepiece comprising an articulated lever connected to a slide by a link. The toepiece may adopt a fitting configuration in which the jaws are spaced apart: this action is obtained by lowering the lever, thereby pushing the slide toward the rear by way of the link. This movement of the slide, by virtue of a ramp, raises the connection between the jaws and causes the jaws to open while loading the springs. A return to the closed configuration, which is adopted going downhill, results from the lowering force on the lever being released and from the return action of the springs. The springs are mounted directly on the jaws. The overall angular travel of the jaws is thus very small and releasing as a result of twisting is not very effective and not very safe.

The aim of the present invention is to propose a solution for binding a boot to a gliding board which remedies the drawbacks listed above.

In particular, a first object of the present invention is to provide a simple, economical and lightweight solution for binding a boot.

A second object of the present invention is to provide a solution for binding a boot that ensures optimum safety for the skier in the event of a fall and limits as far as possible the risks of material deterioration.

In particular, the invention aims to propose a toepiece comprising a releasing system for releasing the boot as a result of twisting of the boot, associated with a heel piece designed to release the boot as a result of a forward fall.

The present toepiece is intended in particular to respect both the touring standard ISO13992 and the alpine standard ISO9462.

These objects may be achieved by a toepiece of a binding device for securing a boot to a gliding board, comprising two rigid jaws that are mounted so as to pivot about respective substantially horizontal axes that are oriented in a substantially longitudinal direction of the toepiece, comprising a releasing system for automatically releasing the boot as a result of twisting of the boot, associated with tilting of the jaws, said toepiece being designed such that, by tilting of at least one jaw, it takes up:

-   -   a closed configuration in which retaining elements carried by         the jaws can engage with the boot,     -   a releasing configuration for releasing the boot as a result of         twisting of the boot, said releasing configuration being         different from the closed configuration, in order to         automatically free the boot by actuation of the releasing         system,     -   a fitting configuration, different from the closed         configuration, in particular different from the releasing         configuration, and allowing the boot to be fitted in the         toepiece between the retaining elements,         the releasing system for automatically releasing the boot as a         result of twisting of the boot comprising an elastic return         means for the jaws in the closed configuration and in the         releasing configuration of the toepiece, the connection between         a jaw and the elastic return means comprising at least one         transmission link articulated to the jaw about a first hinge         axis that is oriented in the longitudinal direction such that         the jaw and its transmission link form a knuckle joint that         deforms in the plane corresponding to the transverse direction         and vertical direction of the toepiece.

The constituent parts of the elastic return means preferably exhibit movements and/or elastic deformations generally in a plane that is oriented in the longitudinal and transverse directions of the toepiece, during the passage from the closed configuration to the releasing configuration and to the fitting configuration.

The transmission link may in particular be articulated to the elastic return means about a second hinge axis that is oriented in the longitudinal direction.

The elastic return means of the releasing system for automatically releasing the boot as a result of twisting of the boot may comprise at least one elastically deformable strip.

Alternatively, the elastic return means may comprise at least one spring and two lever arms that are articulated and/or elastically deformable.

The lever arms may be arranged such that each lever arm makes the connection between one end of said spring that is oriented in the transverse direction and the transmission link connected to one of the jaws.

Alternatively, the elastic return means may comprise two transfer links and a tie bar that is oriented and slides in the longitudinal direction of the toepiece so as to stress said spring that is oriented in the longitudinal direction, each transfer link making the connection between the tie rod and one of the lever arms.

The spring may be disposed in a fixed housing with respect to a base of the toepiece that is intended to be fixed to the gliding board. Alternatively, the spring may be disposed in a housing that is able to move in the longitudinal direction with respect to a base of the toepiece that is intended to be fixed to the gliding board, such that the housing moves at the same time as the tie bar and the spring during the passage from the closed configuration to the fitting configuration and vice versa, and such that the housing remains fixed with respect to the base during the passage from the closed configuration to the releasing configuration and vice versa.

The elastic return means may comprise connecting elements between the two lever arms, allowing the two jaws to move continuously in a synchronous and symmetrical manner with respect to a plane oriented in the longitudinal and vertical directions.

The transmission link connected to the jaw may be articulated by its second hinge axis directly to the lever arm by way of a contact between two spherical surfaces that are respectively carried by the transmission link and by the lever arm. Alternatively, the elastic return means may comprise an offsetting link interposed between each lever arm and the transmission link connected to the jaw, the offsetting link being mounted so as to pivot on the lever arm and on the transmission link and optionally on a base of the toepiece that is intended to be fixed to the gliding board.

The angular tilting travel of a jaw between the closed configuration of the toepiece and the releasing configuration of the toepiece is preferably greater than the angular tilting travel thereof between the closed configuration and the fitting configuration.

The toepiece may comprise an actuating lever that is accessible to the user from outside the toepiece and may take up:

-   -   a fitting position in which the toepiece is placed in the         fitting configuration,     -   a downhill position in which the toepiece is placed in the         closed configuration,     -   and an uphill position in which the releasing system is blocked         so as to block the toepiece in the closed configuration by         preventing any possibility of it passing to the fitting         configuration and/or to the releasing configuration.

The toepiece may comprise a fitting stop that engages with the actuating lever so as to take up an active position in which it forms a support for the boot in the longitudinal direction when the actuating lever is in its fitting position.

The releasing system may comprise means for separating the overall tilting travel of the jaw between the closed configuration and the releasing configuration, into first and second angular sectors that are separated by an intermediate neutral-point position of the jaw corresponding to a hard point of inflection of the jaw under the action of the elastic return means.

A binding device for securing a boot to a gliding board may comprise a toepiece which is intended to secure the front part of the boot, and also a heel piece which is intended to secure a rear part of the boot to the gliding board, the heel piece being designed to release the boot only in the case of a forward fall of the skier, the boot being released from the binding device in the case of a twisting fall only by way of the toepiece.

A gliding board, in particular in the form of a touring ski, may comprise such a toepiece and/or such a binding device.

Further advantages and features will become more clearly apparent from the following description of particular embodiments of the invention, which are given by way of nonlimiting example and are shown in the appended drawings, in which:

FIGS. 1 to 5 are views illustrating a first embodiment of a toepiece according to the invention, adopting a closed configuration,

FIGS. 6 to 9 and 13 are views of the toepiece according to the first embodiment when it adopts a releasing configuration,

FIGS. 10 to 12 are views of the toepiece according to the first embodiment when it adopts an intermediate configuration between the closed configuration and the releasing configuration, at a neutral point of equilibrium,

FIGS. 14 to 18 are views of the toepiece according to the first embodiment when it adopts a fitting configuration,

FIGS. 19 to 23 are views of the toepiece according to the first embodiment when it is blocked in the closed configuration,

FIGS. 24 to 26 are views illustrating a second embodiment of a toepiece according to the invention, adopting a releasing configuration,

FIG. 27 is a view of the toepiece according to the second embodiment when it adopts a closed configuration,

FIG. 28 is a view of the toepiece according to the second embodiment when it adopts an intermediate configuration between the closed configuration and the releasing configuration, at the neutral point of equilibrium,

FIGS. 29 and 30 are views illustrating a third embodiment of a toepiece according to the invention, adopting a closed configuration,

FIGS. 31 and 32 are views of the toepiece according to the third embodiment, when it adopts a releasing configuration and an intermediate configuration at the neutral point of equilibrium, respectively,

FIGS. 33 to 37 are views illustrating a fourth embodiment of a toepiece according to the invention, adopting a closed configuration,

FIGS. 38 and 39 are views of the toepiece according to the fourth embodiment, when it adopts an intermediate configuration at the neutral point of equilibrium,

FIGS. 40 and 41 are views of the toepiece according to the fourth embodiment, when it adopts a releasing configuration,

FIGS. 42 and 43 are views of the toepiece according to the fourth embodiment, when it adopts a fitting configuration,

FIGS. 44 to 46 illustrate, in a top view, a variant of the first embodiment, provided with connecting elements between the lever arms, in the closed configuration, in the intermediate neutral-point configuration and in the releasing configuration, respectively.

The following description, which is given in relation to FIGS. 1 to 32, relates to a toepiece 10 of a binding device for securing a boot 11 to a gliding board (not shown). The term “toepiece” preferably means “front stop” or more generally “front part of the binding device”.

This toepiece 10 binds the front part of the boot 11 and is particularly suitable for ski touring, but does not exclude use in the context of alpine skiing and/or cross-country skiing. More generally, the toepiece 10 is involved in the formation of a binding device for securing the boot 11 to the gliding board, in combination with a rear heel piece (not shown) which binds the rear part of the boot 11.

To make it easier to understand the rest of the description, an orthonormal frame of reference is associated with the toepiece 10, the longitudinal direction X of the toepiece 10 being the horizontal direction oriented from the rear to the front of the toepiece 10. The transverse direction Y thereof corresponds to the horizontal direction perpendicular to the X direction and is oriented from the right to the left of the toepiece 10. The vertical direction Z is perpendicular to the horizontal plane defined by the X and Y directions and is oriented toward the top of the toepiece 10.

Generally, FIGS. 1 to 23 illustrate a first embodiment of the toepiece 10. In particular, FIGS. 3, 8, 12 and 16 illustrate the toepiece 10 on a section plane A-A that can be seen in FIG. 2 and is oriented along a plane (Y, Z) that passes through the jaws defined below. FIGS. 4, 9, 17 and 21 show the toepiece 10 on a section plane B-B that can be seen in FIG. 2 and is oriented along a mid-plane (X, Z) of the toepiece 10. As for FIG. 22, this figure illustrates the toepiece 10 on a section plane C-C that can be seen in FIG. 21 and is also oriented along a plane (Y, Z), but is offset in the forward direction with respect to the section plane A-A, in the longitudinal direction X. FIGS. 24 to 28 show a second embodiment of the toepiece 10, while FIGS. 29 to 32 illustrate a third embodiment of the toepiece 10. For the three embodiments, the reference numerals and letters are retained for identical elements from one embodiment to another. Since the toepiece 10 is generally symmetrical on either side of a mid-plane of symmetry (X, Z), indices “d” and “g” are attached to certain references associated with the respective elements of the right-hand part and of the left-hand part of the toepiece 10.

The toepiece 10, which is part of the binding device for securing the boot 11 to the gliding board, comprises two rigid jaws 12 d, 12 g, on the left and on the right, respectively, that are offset in the Y direction with respect to one another. They are mounted so as to pivot about respective substantially horizontal axes Ad, Ag that are oriented substantially in the longitudinal direction X of the toepiece 10. Each of the jaws 12 d, 12 g is contained in the plane of its movement by tilting, the tilting planes of the two jaws 12 d, 12 g also being coincident with a single plane that is oriented in particular in the Y and Z directions. The pivot axis Ad, Ag of each of the jaws 12 d, 12 g is fixed in a frame of reference connected with the toepiece 10. In particular, these pivot axes may be fixed with respect to a base 20 of the toepiece that is intended to be fixedly mounted to the gliding board, such that the pivot axes are fixed with respect to the gliding board, in particular in the Y and Z directions. Each pivot axis Ad, Ag may be parallel to the longitudinal direction or be contained in a plane (X, Z), that forms an angle of more or less 10 degrees with respect to the horizontal.

As a result, each jaw 12 d, 12 g may tilt, in this tilting plane, over an overall angular travel between a closed position (for example illustrated in FIG. 3 for each of the two jaws 12 d, 12 g) corresponding to a position of the jaw in which it is moved as close as possible to the other jaw over this overall angular travel, and a releasing position (for example illustrated in FIG. 8 for the left-hand jaw 12 g) corresponding to a position of the jaw in which it is spaced as far apart from the other jaw over this overall angular travel. In FIG. 8, the right-hand jaw 12 d takes up its closed position, corresponding to the retaining position of the boot by the jaw 12 d (thus corresponding to the closed configuration of the toepiece, which is defined below), in contrast to the left-hand jaw 12 g, which takes up the releasing position, making it possible to remove the boot laterally in a plane parallel to the X and Y directions. The passage from one position to the other is carried out by tilting the jaw 12 g, 12 d about its pivot axis Ag, Ad over the entire overall angular travel, which is advantageously greater than 30 degrees, in particular greater than 40 degrees, in order to provide this opportunity of releasing as a result of twisting. In each of the three embodiments of the toepiece 10, the overall angular tilting travel of each of the jaws 12 g, 12 d between its two, closed and releasing, positions, referenced α1, is approximately equal to 55 degrees. Although the possibility of tilting of the jaws over the overall angular travel α1 is only illustrated in FIGS. 8, 26 and 31 in relation to the left-hand jaw 12 g in order to allow the boot to be removed from the left-hand side of the toepiece, it is clear that the right-hand jaw 12 d may also tilt, in a symmetrical manner with respect to the mid-plane (X, Z) of the toepiece 10, between closed and releasing positions, in order to allow the boot to be removed from the toepiece on the right-hand side of the toepiece.

Within the angular tilting travel α1 delimited by the closed and releasing positions, each jaw 12 d, 12 g may also take up other intermediate angular positions in a discrete or progressively continuous manner. In particular, each jaw 12 d, 12 g may take up for example an intermediate equilibrium or neutral-point position (illustrated for example in FIG. 12 for the left-hand jaw 12 g, corresponding to the intermediate configuration adopted during a releasing phase, i.e. during the passage from the closed position to the releasing position) and an intermediate fitting position (illustrated for example in FIG. 16 for each of the two jaws 12 d, 12 g, corresponding to a fitting configuration of the toepiece). The angular tilting travel of a given jaw 12 d, 12 g between its closed position and its equilibrium position, referenced α2, is greater than its angular tilting travel referenced α3 between its closed position and its fitting position. By way of example for the first embodiment, the angular tilting travel α2 of each jaw 12 d, 12 g is around 25 to 30 degrees (making it approximately equal to half the overall tilting travel α1) whereas its angular tilting travel α3 is around 20 degrees. Although the possibility of tilting the jaws over the angular travel α2 is only illustrated in FIGS. 12, 28 and 32 in relation to the left-hand jaw 12 g, it is clear that the right-hand jaw 12 d may likewise tilt over an angular travel α2.

The toepiece 10 comprises a releasing system for automatically releasing the boot as a result of twisting of the boot, associated with the tilting of the two jaws 12 d, 12 g over the overall angular tilting travel α1, but also in particular over the partial angular tilting travels α2 and α3. The connection between the jaws 12 d, 12 g that are mounted so as to pivot and the releasing system for automatically releasing the boot as a result of twisting of the boot is such that tilting of either jaw 12 d, 12 g brought about by the boot 11 or by an actuation lever 13, described in detail below, stresses the releasing system in a manner described below. In particular, the assembly may be configured such that synchronous and symmetrical tilting of the two jaws between their intermediate fitting position and their closed position, over the angular travel α2, may be controlled manually by suitable manipulation of the actuating lever 13. On the other hand, the assembly may be configured such that synchronous and symmetrical tilting of the two jaws from their fitting position to the closed position may be controlled or at least encouraged by a vertical downward movement, brought about by the skier, of the boot 11 in the Z direction between the jaws 12 d, 12 g, as is explained below, by virtue of the bearing surfaces 24 d, 24 g secured to the jaws or even by virtue of a fitting pedal independent of the jaws. Finally, the assembly is in particular configured such that the application of forces in the plane (X, Y) transmitted by the boot 11 to at least one jaw 12 during a twisting movement of the boot 11, i.e. having at least one force component exerted in the transverse direction Y, controls tilting of at least one of the two jaws 12 d, 12 g from its closed position over a given angular travel less than or equal to the overall angular tilting travel α1.

The toepiece 10 is configured, in particular by way of a suitable design of its releasing system for automatically releasing the boot as a result of twisting of the boot, such that, by tilting at least one of the jaws 12 d, 12 g, it takes up:

-   -   a configuration known as a “closed” configuration (illustrated         for example in FIGS. 1 to 5 for the first embodiment) in which         the jaws 12 d, 12 g are moved toward one another such that the         retaining elements 14 d, 14 g carried respectively by the jaws         12 d, 12 g take up positions enabling them to engage with the         boot 11 to ensure that it is secured in its front part,     -   and at least one configuration known as a “releasing         configuration” for releasing the boot as a result of twisting of         the boot (illustrated for example in FIGS. 6 to 13 for the first         embodiment) in which the jaws 12 d, 12 g are spaced apart from         one another for safety reasons, in particular in the event of a         twisting fall, by the implementation of automatic actuation of         the releasing system (this implementation resulting from the         forces applied by the boot 11 to at least one of the jaws 12 d,         12 g during a twisting movement in the plane (X, Y) or in a         plane having a non-0 Y component, other than the plane (X, Z))         making it possible to automatically free the boot 11 from the         jaws, by moving the retaining elements 14 d, 14 g out of the         boot 11 which can then be separated from the gliding board so as         not to injure the skier. This is a different configuration from         the closed configuration to the extent that at least one of the         jaws takes up a different position.

Thus, the releasing configuration is automatically taken up in particular in the event of a twisting fall, whether or not this is of the purely twisting type, i.e. is possibly combined with a forward fall and/or a backward fall of the skier.

These closed and releasing configurations are the stable configurations of the toepiece, to the extent that the toepiece remains in this configuration when no action is being applied to the jaws.

In the second embodiment of the toepiece 10, the closed configuration is shown in FIG. 27. In the third embodiment of the toepiece 10, the closed configuration is shown in FIGS. 29 and 30.

Specifically, the closed configuration of the toepiece 10 corresponds to a state of the latter in which each of the two jaws 12 d, 12 g is placed in its closed position. This definition may be applied to the three embodiments.

The above description of the releasing configuration should be interpreted as implying that the angular tilting travel of at least one jaw 12 d, 12 g between the closed configuration of the toepiece and the releasing configuration of the toepiece for releasing the boot as a result of twisting of the boot is such that the boot 11 may escape from the space between the jaws 12 d, 12 g by way of a movement of the boot 11 that has at least one component in the transverse direction Y, optionally linked with a vertical upwardly directed component in the Z direction. This angular tilting travel is advantageously greater than about 40 degrees, in particular greater than 45 degrees, for example approximately equal to 55 degrees, such that in the releasing configuration, the boot 11 may escape freely from the space between the jaws 12 d, 12 g by way of an approximately horizontal movement of the boot 11 in the longitudinal direction X and the transverse direction Y, passing above at least one jaw 12 d, 12 g, in particular above the one that has been subjected to tilting for releasing the boot as a result of twisting.

FIGS. 6 to 9 and 13 illustrate the toepiece 10 according to the first embodiment when it adopts such a releasing configuration as a result of twisting of the boot. Specifically, it corresponds to a state of the toepiece 10 in which at least one of the jaws, in this case the left-hand jaw 12 g only, is placed into its releasing position. The other jaw may possibly, as is shown, remain in its closed position. Said at least one jaw which has been subjected to tilting over an overall angular travel α1 corresponds to the jaw which has been subjected to the forces applied by the boot 11 during its twisting movement. This configuration is illustrated in FIGS. 24 to 26 for the second embodiment and in FIG. 31 for the third embodiment.

FIGS. 10 to 12 illustrate an intermediate configuration of the toepiece during a phase of releasing the boot as a result of twisting of the boot, during the passage from the closed configuration to the releasing configuration. Specifically, this configuration of the toepiece 10 corresponds to a state of the latter in which at least one of the jaws, in this case the left-hand jaw 12 g only, is placed into its intermediate equilibrium position. The other jaw may possibly, as is shown, remain in its closed position. Said at least one jaw which has been subjected to tilting over a partial angular travel α2 corresponds to the jaw which has been subjected to the forces applied by the boot 11 during its twisting movement. This is an intermediate configuration reached temporarily during the passage from the closed position to the releasing configuration of the toepiece or vice versa, this configuration being unstable to the extent that the toepiece 10, even when no action is applied to the jaws, does not remain permanently in this configuration but, on the contrary, will automatically adopt either the stable releasing configuration or the stable closed configuration.

The releasing system for automatically releasing the boot as a result of twisting of the boot is advantageously configured such as to be able to allow independent tilting of the two jaws 12 d, 12 g with respect to one another. In other words, as is shown, the left-hand jaw 12 g may tilt about the axis Ag during the actuation of the releasing system, whereas the right-hand jaw 12 d remains fixed, or vice versa. In particular, the passage of the toepiece 10 from the closed configuration to the releasing configuration results from tilting of a single jaw 12 d, 12 g about its pivot axis Ad, Ag under the effect of the application of forces transmittal by the boot 11 to this jaw 12 d, 12 g during the twisting movement of the boot 11, the other jaw possibly being able to remain fixed. More generally, the releasing system for automatically releasing the boot as a result of twisting of the boot is configured so as to automatically place the toepiece 10 in the releasing configuration from the closed configuration when, in the closed configuration, a twisting force greater than a predetermined threshold is applied by the boot 11 to at least one of the jaws. Advantageously, the releasing system is configured such that the predetermined threshold is such that, in a general manner, the toepiece may release the boot as a result of twisting for values of Z according to standard ISO9462, preferably between 3 and 16.

Advantageously, the retaining elements 14 d, 14 g are configured such that, in the closed configuration, the front part of the boot 11 is secured to the jaws 12 d, 12 g in the plane (X, Y), maintaining a possibility for the boot 11 to pivot with respect to the toepiece 10 about an axis with the reference “T” (FIG. 23) which is oriented in the transverse direction Y of the toepiece 10. Such an arrangement makes it possible to use this toepiece 10 within the scope of ski touring. FIG. 23 illustrates the situation in which the boot 11 has been subjected to pivoting about the axis T by an angle of around 90 degrees with respect to the situation in FIGS. 5, 13 and 18. Each retaining element 14 d, 14 g may have any desired nature and shape, depending for example on those of the boot 11. However, in the three particular embodiments, each retaining element 14 d, 14 g advantageously has a generally conical shape, in particular in the form of an ogive, so as to engage with a complementary impression 15 in the boot 11. In particular, the end of the tip of the ogive may have a surface having a spherical shape. The effect of these arrangements is to encourage the freeing of the boot 11 by removing the retaining elements 14 d, 14 g from the front part of the boot 11 if the releasing system for automatically releasing the boot as a result of twisting of the boot is actuated toward the releasing configuration, avoiding at most any risk of the boot 11 being blocked in the jaws, in order to provide optimum safety.

The toepiece 10 is configured such that, by tilting at least one jaw 12 d, 12 g, in particular by tilting the two, left-hand and right-hand, jaws 12 g, 12 d in a synchronous and symmetrical manner in a plane (Y, Z), it also takes up a configuration known as a “fitting” configuration (illustrated for example in FIGS. 14 to 18 for the first embodiment) enabling the boot 11 to be placed in the toepiece 10 between the retaining elements 14 d, 14 g. The fitting configuration, when it results from synchronous tilting of the two jaws, is not shown for the second and third embodiments of the toepiece 10. It is once again an unstable configuration, different from the closed configuration and potentially also from the releasing configuration. The fitting configuration is in particular adopted by the implementation, from the closed position, of tilting imposed on at least one of the jaws toward the outside of the toepiece in order to allow the boot to move between the retaining elements 14 d, 14 g. The angular tilting travel (α1) of a jaw between the closed configuration of the toepiece and the releasing configuration of the toepiece is greater than its angular tilting travel (α3) between the closed configuration of the toepiece and the fitting configuration of the toepiece.

The fitting configuration may correspond:

-   -   either to the result of tilting of at least one of the jaws that         is imposed before the action of placing the boot between the         retaining elements, for example with the aid of the actuating         lever described below: in this case, the toepiece may adopt the         fitting configuration even when the boot is not being fitted:     -   or to the result of tilting of at least one of the jaws that is         imposed by the very action of placing the boot between the         retaining elements: in this case, it is the action of the boot         during fitting which causes the toepiece to move from the closed         configuration to the fitting configuration.

In particular, this action of placing the boot between the retaining elements may result from a downward movement of the boot in the Z direction and optionally a forward movement thereof in the X direction.

Specifically, the fitting configuration of the toepiece 10 may correspond to a state of the latter in which each of the two jaws 12 d, 12 g is placed in its intermediate fitting position, for example following an angular travel equal to α3 from the closed position adopted previously in the closed configuration of the toepiece 10. However, it remains possible to provide for one jaw to be able possibly to continue to occupy its closed position when the toepiece 10 takes up its fitting configuration, depending for example on the nature and the design of the jaws 12 d, 12 g, of the retaining elements 14 d, 14 g and of the impressions 15.

Advantageously, the releasing system comprises means for separating the overall angular tilting travel α1 of the jaw 12 d, 12 g into first and second angular sectors that are separated by an intermediate neutral-point or equilibrium position of the jaw 12 d, 12 g corresponding to a hard point of inflection of the jaw under the action of an elastic return means (defined below). In other words, the overall angular travel α1 is separated:

-   -   into a first angular sector separating the closed position of         the jaw 12 d, 12 g (taken up for example in the closed         configuration) and the intermediate neutral-point or equilibrium         position of the jaw 12 d, 12 g, corresponding to the angle α2         temporarily adopted during the releasing phase,

and a second angular sector separating the releasing position of the jaw 12 d, 12 g (taken up for example in the releasing configuration) and the intermediate neutral-point position of the jaw 12 d, 12 g.

The jaws are energized by the elastic return means into all of the configurations, namely the closed configuration, the releasing configuration and the fitting configuration. At the moment of releasing the boot as a result of twisting of the boot, the position of the jaws is located angularly beyond the fitting position.

In order to ensure that the elastic return means may be involved in, or may itself ensure, automatic returning of the toepiece 10 into the closed configuration from its fitting configuration, the angular position of the jaw 12 d, 12 g that is taken up in the fitting configuration is included in the first angular sector defined in the previous paragraph.

The elastic return means belongs to the releasing system and is configured in particular to ensure that the jaws return into the closed configuration and into the releasing configuration of the toepiece as soon as the latter is no longer in these two configurations. It is stressed by the tilting of the jaws 12 d, 12 g toward the outside: the tilting of the jaw 12 d, 12 g from the closed position to the intermediate neutral-point position is accompanied by increasing compression of the elastic return means, while the tilting of the jaw 12 d, 12 g from the intermediate neutral-point position to the releasing position is accompanied by decreasing compression of the elastic return means.

Advantageously, the releasing system for automatically releasing as a result of twisting comprises at least one transmission link 16 d, 16 g connected to each jaw 12 d, 12 g. Thus, the system for automatically releasing comprises at least one right-hand transmission link 16 d articulated to the right-hand jaw 12 d about a first hinge axis Bd that is oriented in the direction X such that the right-hand jaw 12 d and its right-hand transmission link 16 d form a right-hand knuckle joint that deforms in the plane (Y, Z). In a symmetrical manner with respect to the mid-plane (X, Z) of the toepiece 10, the automatic releasing system comprises at least one left-hand transmission link 16 g articulated to the left-hand jaw 12 g about a first hinge axis Bg that is oriented in the longitudinal direction X such that the left-hand jaw 12 g and its left-hand transmission link 16 g form a left-hand knuckle joint that deforms in the plane (Y, Z). One advantage of fitting at least one transmission link 16 d, 16 g of this type is that the releasing system has a very small space requirement, notwithstanding a very large overall angular travel of the jaws for ensuring releasing as a result of twisting of the boot. In the embodiment shown, the articulation of the transmission link to the jaw is provided in the region of an extension, with the reference 27 d, 27 g (FIG. 8), of the jaw in the direction of the interior of the toepiece 10.

Close to its opposite end, the right-hand transmission link 16 d is articulated directly or indirectly to the elastic return means about a second hinge axis Cd that is oriented in the longitudinal direction X. The left-hand transmission link 16 g is likewise articulated directly or indirectly to the elastic return means about a second hinge axis Cg that is oriented in the longitudinal direction X.

The intermediate neutral-point position of the right-hand jaw 12 d corresponds, in this variant, to relative positioning of the right-hand jaw 12 d and of the right-hand transmission link 16 d in which the pivot axis Ad of the right-hand jaw 12 d, the first hinge axis Bd and the second hinge axis Cd of the right-hand transmission link 16 d are all aligned along a single straight line. With such particular positioning, the right-hand knuckle joint adopts its configuration of maximum extension so as to stress the elastic return means at a maximum value of forces corresponding to the hard point of inflection of the right-hand jaw. In other words, over the rest of the overall angular tilting travel α1 of the right-hand jaw 12 d, the amount of stress applied to the elastic return means by the right-hand transmission link 16 d is less than that which is particularly adopted at the hard point of inflection.

By symmetry in relation to the mid-plane (X, Z) of symmetry of the toepiece 10, the intermediate neutral-point position of the left-hand jaw 12 g corresponds, in this variant provided with transmission links 16 d, 16 g, to relative positioning of the left-hand jaw 12 g and of the left-hand transmission link 16 g in which the pivot axis Ag of the left-hand jaw 12 g, the first hinge axis Bg and the second hinge axis Cg of the left-hand transmission link 16 g are all aligned along the same straight line. This particular positioning is shown in FIGS. 12, 28 and 32 for the first, second and third embodiments, respectively. With such particular positioning, the left-hand knuckle joint adopts its configuration of maximum extension so as to stress the elastic return means at a maximum value of forces corresponding to the hard point of inflection of the left-hand jaw. In other words, over the rest of the overall angular tilting travel α1 of the left-hand jaw 12 g, the amount of stress applied to the elastic return means by the left-hand transmission link 16 g is less than that which is particularly adopted at the hard point of inflection.

In the first and third embodiments of the toepiece 10, the elastic return means of the releasing system comprises at least one spring 17 and two lever arms 18 d, 18 g which are articulated and/or elastically deformable and are arranged such that each lever arm 18 d, 18 g makes the connection between one end of the spring 17 and the transmission link 16 d, 16 g connected to one of the jaws 12 d, 12 g. In the first embodiment, the transmission link 16 d, 16 g connected to the jaw 12 d, 12 g is articulated by way of its second hinge axis Cd, Cg directly to the lever arm 18 d, 18 g. The articulation of the transmission link to the corresponding lever arm is brought about by contact between a spherical surface of the transmission link 16 d, 16 g and a complementary spherical surface formed in the lever arm, making it possible to minimize the vertical movement of the articulation point. In the third embodiment of the toepiece 10 with reference to FIGS. 29 to 32, the elastic return means comprises an offsetting link 19 d, 19 g interposed between each lever arm 18 d, 18 g and the transmission link 16 d, 16 g connected to the jaw 12 d, 12 g. The offsetting link 19 d, 19 g is mounted so as to pivot on the lever arm 18 d, 18 g and on the transmission link 16 d, 16 g, and optionally on a base 20 of the toepiece 10 that is intended to be fixed to the gliding board. In the third embodiment, the articulation of the transmission link to the corresponding offsetting link is realized by a hinge axis. The advantage of this solution is that only pivot axes are used, limiting friction within the connection between the jaw and the return spring.

The spring 17 is oriented in the transverse direction Y of the toepiece 10 in the first and third embodiments, but any other orientation may be suitable. The advantage of this orientation is to favor a small vertical space requirement of the releasing system. In the first embodiment of the toepiece 10, the spring 17 is arranged behind the jaws 12 d, 12 g in the longitudinal direction X. By contrast, in the third embodiment of the toepiece 10, the spring 17 is arranged in front of the jaws 12 d, 12 g.

In the first embodiment, each lever arm 18 d, 18 g is articulated to a base 20 of the toepiece 10 that is intended to be fixed to the gliding board, about a hinge axis Dd, Dg oriented in the vertical direction Z. In the longitudinal direction X, the region of articulation of the transmission link 16 d, 16 g on the corresponding lever arm 18 d, 18 g is interposed between the hinge axis Dd, Dg and the region of connection of the lever arm 18 d, 18 g to the spring 17. As a result, the lever arm 18 d, 18 g ensures a demultiplication function between the movement (for example around 2 mm) imposed on the lever arm 18 d, 18 g by the transmission link 16 d, 16 g and the movement (for example around 6 mm) imposed by the lever arm 18 d, 18 g on its region of connection to the spring 17. The demultiplication ratio depends on the ratio between firstly the distance along X between the hinge axis Dd, Dg and the region of connection to the spring 17 and secondly the distance along X between the hinge axis Dd, Dg and the point of articulation to the transmission link 16 d, 16 g. In the third embodiment, the offsetting links 19 d, 19 g are configured so as to impart a demultiplication function added to that of the lever arms 18 d, 18 g. This demultiplying lever arm 18 d, 18 g makes it possible to use a spring 17 that has low stiffness and thus advantageously a low space requirement. For example, for a Z according to the standard ISO9462 having a value of 12, a spring 17 having a stiffness of around 20 N/mm may be used, this being much less than the stiffnesses of springs conventionally used in alpine binding toepieces, which are commonly around 100 N/mm.

In addition, the toepiece may comprise a regulating system 28 (FIG. 1) for adjusting the stiffness of the spring 17, for example of the screw-nut type.

FIG. 11 illustrates the situation of the lever arms 18 d, 18 g when the left-hand knuckle joint is in maximum extension so as to pivot the left-hand lever arm 18 g to the maximum, the latter bringing about maximum movement of its region of connection to the spring 17 in comparison with the movement of the region of connection to the spring 17 during the rest of the overall angular tilting travel α1 of the left-hand jaw 12 g. Since the stress force of the spring 17 depends more or less proportionally on the movement of its region of connection to the lever arm 18 d, 18 g, it is in this particular configuration that the stress force of the spring 17 is at a maximum, so as to form the hard point of inflection defined above and associated with the neutral-point position of the left-hand jaw 12 g. The principle is symmetrically identical for the right-hand jaw 12 d.

Specifically, FIG. 2 illustrates the situation of the lever arms 18 d, 18 g when the toepiece 10 adopts its closed configuration: they are at rest, parallel to one another in the X direction and stress the spring 17 little, if at all. When, for example, the left-hand jaw 12 g tilts along its overall angular tilting travel α1 and thus travels through the first and second angular sectors, by automatic actuation of the releasing system under the effect of twisting forces applied by the boot 11 during the twisting movement in order to cause the toepiece 10 to adopt its releasing configuration, the lever arms 18 d, 18 g occupy the situation in FIG. 7: the right-hand lever arm 18 d remains at rest and the left-hand lever arm 18 g, after the left-hand jaw 12 g has passed both the hard point of inflection illustrated in FIG. 11 and the second angular sector, takes up the configuration in FIG. 7, in which it is at a deviation angle with respect to the longitudinal direction X that is less than the deviation angle which it forms at rest in FIG. 11. The stress forces of the spring 17 are thus less, although the tilting of the left-hand jaw 12 g is greater so as to allow releasing the boot as a result of twisting of the boot. Similarly, FIG. 15 illustrates the situation of the lever arms 18 d, 18 g when the two jaws are each tilted to an angle included in the first angular sector so that the toepiece 10 adopts the fitting configuration. In this case again, each lever arm 18 d, 18 g is at a deviation angle with respect to the longitudinal direction X that is less than the deviation angle which it can form at a maximum, as in FIG. 11 for the left-hand lever arm 18 g. The stress forces of the spring 17 are thus less and, on account of remaining in the first angular sector without passing the hard point, the spring 17 may return the toepiece 10 into the closed configuration in FIG. 2 by way of the lever arms 18 d, 18 g under the effect of the stress forces of the spring 17.

The connection between one end of the spring 17 and the lever arm 18 d, 18 g is of the inset type in the figures. Thus, the pivoting of a given lever arm 18 d, 18 g causes the spring 17 to operate in flexion. Alternatively, it is possible to provide, for each of the first and third embodiments of the toepiece 10, for the connection between the end of the spring 17 and the lever arm 18 d, 18 g to be a ball-joint connection allowing the spring 17 to operate only in tension and/or compression and no longer to operate in flexion.

In the second embodiment of the toepiece 10 with reference to FIGS. 24 to 28, the elastic return means of the releasing system comprises at least one elastically deformable strip 21 for example in the form of a U₁ in particular made of plastics material, metal or composite material. The strip 21 may have any desired spatial orientation, for example be generally contained in a plane (X, Y) in order to limit the vertical space requirement along Z of the system for releasing as a result of twisting. Each of the lateral arms 21 d, 21 g of the strip 21 is articulated to the transmission link 16 d, 16 g connected to a given jaw 12 d, 12 g. The automatic releasing system for automatically releasing the boot as a result of twisting of the boot is configured such that the transmission link 16 d, 16 g articulated to a given lateral arm 21 d, 21 g of the strip 21 exerts a mechanical stress on the lateral arm 21 d, 21 g, tending to deform it elastically in the direction of the other lateral arm 21 d, 21 g of the strip 21 when the jaw 12 d, 12 g connected to this transmission link 16 d, 16 g moves toward its intermediate neutral-point position. The operating principle remains identical to that described above in the case of a spring 17 combined with two lever arms, except for the fact that the demultiplication function is carried out by each of the lateral arms 21 d, 21 g. This blade operates in flexion by means of an inset connection in the region of its connection to the base 20. The U-shape of the strip 21 may be replaced by the arrangement of two separate independent strips.

As explained above, the toepiece 10 advantageously comprises an actuating lever 13 which is intended for manual actuation and to this end is accessible to the user from outside the toepiece 10. The lever 13 is configured such that it can take up:

-   -   a position known as the “fitting” position (adopted in FIGS. 14,         17 and 18) in which the toepiece 10 is placed in the fitting         configuration, in order to allow the skier to fit the toepiece         10,     -   a position known as the “downhill” position (adopted in FIGS. 1,         4, 5, 29 and 30) in which the toepiece 10 is placed in the         closed configuration in order to allow the skier to descend         slopes with an toepiece 10 that ensures safety by releasing the         boot as a result of twisting,     -   and a position known as the “uphill” position (adopted in FIGS.         19 and 21 to 23) in which the operation of the automatic         releasing system for releasing the boot as a result of twisting         of the boot is blocked so as to block the toepiece 10 in the         closed configuration by preventing any possibility of the         toepiece 10 passing into the fitting configuration and/or into         the releasing configuration, in order to allow the skier to move         uphill while preventing any accidental release of the toepiece         10.

In its fitting position, a part of the lever 13 comes into contact with the free ends of the lever arms 18 d, 18 g, that is to say on the side opposite their connection to the spring 17, in order to space apart the lever arms in order to place the jaws in the fitting configuration of the toepiece and to maintain them there in a stable manner.

Such an actuating lever 13 is for example arranged in front of the jaws 12 d, 12 g in the longitudinal direction X and is configured so as to vary the position by way of a tilting movement about a pivot axis having the reference “D” in FIG. 1, for example oriented parallel to the transverse direction Y.

In FIG. 22, which illustrates the toepiece 10 in a section plane C-C in front of the jaws in the longitudinal direction X, two blocking elements 26 d, 26 g are shown, said blocking elements 26 d, 26 g surrounding the two lever arms 18 d, 18 g by being interposed transversely between the base 20 and the lever arms when the latter adopt the rest configuration (corresponding to the closed configuration of the toepiece 10) in FIG. 2. The blocking elements 26, which are secured to the actuating lever 13, thus prevent any pivoting movement of the lever arms 18 d, 18 g about the axes Dd and Dg, only when the lever 13 adopts its uphill position (the highest possible position). This action on the lever arms has the effect of inhibiting the operation of the releasing system for releasing as a result of twisting, thereby preventing any possibility of the toepiece 10 moving into its fitting configuration or into its releasing configuration.

The toepiece 10 also advantageously comprises a fitting stop 22 that engages, by way of at least one connecting link 25 configured in an appropriate manner, with the actuating lever 13 so as to take up an active position (FIG. 17) in which it protrudes from the rest of the base 20. In this active position, which is adopted at least when the actuating lever 13 is in its fitting position, the fitting stop 22 forms a support for the boot 11 in the longitudinal direction X. The fitting stop 22 is partially retracted under the base 20 when the lever 13 adopts its downhill position (FIG. 4) in which the toepiece 10 is placed in its closed configuration, maintaining the possibility of actuating the releasing system. It is then retracted entirely under the base 20 when the lever 13 adopts its uphill position (FIG. 21), with any possibility of actuating the releasing system being blocked. As a result of being moved aside in this way, the fitting stop 22 frees the space between the front region of the boot 11 in order to allow it to pivot upward about the axis T when moving uphill with the aid of the touring ski.

Each jaw 12 d, 12 g comprises a bearing surface 24 d, 24 g (which can be seen in FIGS. 14 and 16) that forms a fitting pedal, said bearing surface 24 d, 24 g being configured to form a support for the boot 11 in the vertical direction Z. This support is such that a movement of the boot 11 (when it is bearing against the bearing surfaces 24 d, 24 g) in the downward direction and thus in the direction of the gliding board in the vertical direction Z, is involved in the passage of the toepiece 10 from the fitting configuration (FIGS. 14 and 16) or the releasing configuration to the closed configuration. The bearing surfaces 24 d, 24 g are also configured so as each to form a support along Z such that a passage of the toepiece 10 from the closed configuration into the fitting configuration and/or into the releasing configuration raises the boot 11 in the vertical upward direction Z in a direction away from the gliding board so as to make it easier to interrupt the engagement between the retaining elements 14 d, 14 g and the boot 11. The bearing surfaces 24 d, 24 g are formed in the region of the extensions 27 d, 27 g.

FIGS. 33 to 43 show a fourth embodiment of a toepiece 10 according to the invention. The same reference numerals are retained for identical elements with respect to the first three embodiments.

This fourth embodiment still comprises the two rigid jaws 12 d, 12 g that are mounted so as to pivot about respective substantially horizontal axes that are oriented substantially in the substantially longitudinal direction X of the toepiece. The elastic return means also comprises two lever arms 18 d, 18 g that are elastically deformable and/or mounted so as to pivot about vertical axes.

As above, the connection between a jaw 12 d, 12 g and each lever arm 18 d, 18 g comprises at least one transmission link 16 d, 16 g articulated to the jaw such that the jaw and its transmission link form a knuckle joint that deforms in the plane corresponding to the transverse direction Y and the vertical direction Z of the toepiece.

The fourth embodiment differs from the first embodiment in that the spring 17 is oriented in the longitudinal direction X, by the existence of a tie bar 30 which is mounted inside the spring 17 and bears against one of its ends, and by the presence of transfer links 29 d, 29 g. The tie bar 30 is oriented in the longitudinal direction X and may slide in this direction X. Each transfer link 29 d, 29 g makes the connection between a lever arm and one end of the tie bar 30, for example a rear end along X. The pivot axis of each transfer link 29 d, 29 g on the corresponding lever arm 18 d, 18 g is vertical, as is the pivot axis of each transfer link 29 d, 29 g on the tie bar 30. Thus, the transfer links, like the lever arms, move and/or are deformed in a plane oriented in the X and Y directions. The tie bar 30 stresses the spring 17 in a manner detailed below.

The spring 17 is arranged in a housing 31 which may be able to move in the longitudinal direction X with respect to the base of the toepiece that is intended to be fixed to the gliding board, in such a manner that:

-   -   the housing 31 moves at the same time as the tie bar 30 and the         spring 17 during the passage from the closed configuration to         the fitting configuration and vice versa (FIGS. 42 and 43),     -   the housing 31 remains fixed with respect to the base during the         passage from the closed configuration to the releasing         configuration and vice versa (FIGS. 38 and 39).

The fourth embodiment also comprises a system 28 for regulating the stiffness of the spring 17, said system being accessible for example from the front of the toepiece in the X direction. The regulating system 28 is formed by a screw-nut system, the screw being formed by a part 30 a of the tie bar 30 and the nut being formed by the other part 30 b of the tie bar 30. The transfer links 29 d, 29 g are articulated to this nut. The toepiece also comprises an actuating lever 13 that pivots about the axis D (FIG. 37). The toepiece also comprises a drive part 32 arranged between the actuating lever 13 and the housing 31. The drive part 32 is mounted so as to pivot with respect to the base about a transverse axis having the reference 36 and with respect to the housing 31 about a transverse axis having the reference 35.

The fourth embodiment functions as follows.

At rest, the toepiece is in the closed configuration shown in FIGS. 33 to 37. When a transverse force is applied to one of the jaws 12 d, 12 g by the boot, in particular in the case of a fall, the stressed jaw pivots. On this side of the toepiece, the jaw and the corresponding transmission link 16 d, 16 g form a knuckle joint that deforms in the plane corresponding to the transverse direction Y and vertical direction Z of the toepiece. This causes the lever arm 18 d, 18 g in contact with the transmission link to be driven transversely. The lever arm is deformed and/or pivots in a plane (X, Y), as does the transfer link 29 d, 29 g articulated to this lever arm. As a result, the tie bar 30 slides in the X direction in a manner stressing the spring 17. The more the tie bar 30 is moved, for example toward the rear of the toepiece along X, the more the spring 17 is stressed and thus compressed.

At the same time, the sliding of the tie bar 30 causes a symmetrical movement of the other transfer link 29 d, 29 g. The lever arm 18 d, 18 g articulated to the latter pivots and/or is deformed in a symmetrical and synchronous manner with the other lever arm 18 d, 18 g. As a result, by way of the other transmission link 16 d, 16 g, the other jaw 12 d, 12 g, that is to say the one which has not been subjected to a transverse force by the boot, pivots in a synchronous and symmetrical manner with respect to a plane (X, Z) with the jaw which has been subjected to this force.

When the transmission links 16 d, 16 g pass beyond their intermediate neutral-point position (FIGS. 38 and 39), the spring 17 tends to push the tie bar 30 back in an opposite sliding direction, for example toward the front of the toepiece along X, tending to move it back into its position that is taken up in the closed configuration of the toepiece. Thus, while the jaw stressed by the boot pivots from the intermediate neutral-point position into the open position for releasing, the tie bar 30 returns to its normal position. The tie bar thus carries out a forward movement along X during the passage from the closed configuration to the intermediate neutral-point configuration, stressing the spring 17, whereas it carries out an opposite return movement, under the return effect imparted by the spring 17, during the passage from the intermediate neutral-point configuration to the releasing configuration.

As indicated above, during the forward movement of the tie bar 30, the two jaws pivot synchronously and symmetrically. However, during the return movement of the tie bar 30, only the jaw which has been subjected to the force of the boot continues to pivot into the completely open position, in contrast to the one which has not been subjected to the force of the boot and, for its part, returns to its closed position. FIGS. 40 and 41, which show the toepiece in the releasing configuration (in the particular case in which the left-hand side is released), illustrate this situation where the right-hand jaw 12 b is in the closed position and the left-hand jaw is in its open position.

During the forward and return movements of the tie bar 30, the housing 31 remains fixed with respect to the base that is fixed to the gliding board. Therefore, the opposite end of the tie bar 30 along X to the end at which the two transfer links 29 d, 29 g are articulated, is provided with a bearing surface 37 for one end of the spring 17, while the other end of the spring 17 bears against a shoulder 38 of the housing 31.

In order to pass the toepiece 10 from the configuration for releasing as a result of twisting, which is a stable configuration, to the closed configuration, which is also a stable configuration, the user must raise the jaw, which has been subjected to the force of the boot and which is in its open position, into the releasing configuration. The movements and/or deformations of the parts of the elastic return means, in particular of the tie bar 30, the transfer links 29 d, 29 g and the lever arms 18 d, 18 g, are identical to those during the passage from the closed configuration to the releasing configuration.

The passage from the closed configuration to the fitting configuration is carried out by lowering the actuating lever 13, thus making it pivot about the axis D. Tabs 39 of the actuating lever 13 push the drive part 32, which for its part then pivots about the axis 36. By way of the pivot axis 35 fixed to the housing 31, the drive part 32 causes the housing 31 to slide in translation in the X direction. The base comprises sliding guiding means 40 for guiding the housing 31 in the longitudinal direction X. This sliding of the housing 31 causes an identical sliding movement of the spring 17 and of the tie bar 30. This joint movement of the tie bar 30, of the spring 17 and of the housing 31 has the effect of causing a pivoting movement of the jaws from their closed positions, by way of the transfer links 29 d, 29 g, the lever arms 18 d, 18 g and the transmission links 16 d, 16 g. In other words, the lowering of the lever 13 causes the toepiece to pass into its fitting configuration (FIGS. 42 and 43). Advantageously, during this passage, the spring 17 remains fixed with respect to the housing 31. Therefore, said spring is neither compressed nor stressed: the force to be exerted on the actuating lever 13 is constant and independent of the stiffness of the spring 17, which is regulated via the regulating system 28.

The toepiece also comprises a return spring 33 interposed between the base and the tie bar 30, at that end of the tie bar 30 that is opposite the end that bears against the spring 17. When the assembly comprising the tie bar 30, the spring 17 and the housing slides in one piece during the lowering of the lever 13, the return spring 33 is compressed. As soon as the user stops applying pressure to the lever 13, the return spring 33 allows this assembly to return into the same configuration that was adopted in the closed configuration of the toepiece: the force applied by the return spring 33 on the tie bar 30 returns the tie bar, the housing and thus the lever 13 into the initial position via the drive part 32. However, the return spring 33 is optional and the actuating lever 13 may be returned into the raised position by way of an action applied to the lever 13 by the user himself.

In a variant of the fourth embodiment which is not shown, the spring 17 is disposed in a housing which is permanently fixed with respect to a base of the toepiece that is intended to be fixed to the gliding board. The drive part 32 may advantageously be omitted for reasons of simplicity and weight, and in this case, it is the actuating lever 13 which is directly articulated to the tie bar 30 and which stresses it in translation along X during the passage into the fitting configuration of the toepiece, thus also stressing and compressing the spring 17.

FIGS. 44 to 46, finally, show a variant of the first embodiment, which could also be adapted to the fourth embodiment. Essentially, the elastic return means comprises connecting elements 34 between the two lever arms 18 d, 18 g, allowing the two jaws 12 d, 12 g to move continuously in a synchronous and symmetrical manner with respect to a plane oriented in the longitudinal and vertical directions. In FIGS. 45 and 46, in the intermediate neutral-point configuration and in the releasing configuration, respectively, the two lever arms 18 d, 18 g are still symmetrical with respect to a mid-plane (X, Z). These are, in particular, connecting elements 34 which ensure a mechanical connection between the two lever arms 18 d, 18 g such that the two lever arms 18 d, 18 g move continuously in a synchronous and symmetrical manner with respect to a plane oriented in the longitudinal and vertical directions. Such connecting elements 34 are obtained, for example, by way of first elements, for example of the female type, which are secured to the right-hand lever arm 18 d and engage by way of a form fit with second elements, for example of the male type, that are secured to the left-hand lever arm 18 g. The engagement by way of a form fit may allow an articulation between the first and second elements, in particular about a vertical axis.

In order to make the solution as reliable as possible, the toepiece 10 comprises a protective housing 23 enclosing all or part of the releasing system for releasing the boot as a result of twisting. The protective housing 23 and its means for securing to the rest of the toepiece 10 are designed either so as to seal the assembly with respect to snow and moisture (and also in order to protect the lubrication of the system by way of grease, for example), or so as to potentially allow snow to escape toward the outside of the releasing system.

In all of the above-described embodiments, the constituent parts of the elastic return means exhibit movements and/or elastic deformations generally in a plane oriented in the longitudinal direction X and transverse direction Y of the toepiece, during the passage from the closed configuration into the releasing configuration and into the fitting configuration. The optional lever arms 18 d, 18 g are mounted so as to pivot about a vertical axis and/or deform in a plane (X, Y). The optional transfer links are mounted so as to pivot about vertical axes and/or deform in a plane (X, Y). The optional tie bar 30 slides along direction X. The spring 17 deforms in a plane (X, Y), being oriented for example along direction Y (first embodiment) or along direction X (fourth embodiment). The optional offsetting links 19 d, 19 g pivot about an axis X. All of these movements and deformations of the constituent parts of the elastic return means thus take place in a plane that is generally perpendicular to the deformation plane of the knuckle joint formed by a jaw and its associated transmission link.

Finally, as indicated above, the binding device for securing the boot 11 to the gliding board comprises both such a toepiece 10 that is intended to secure the front part of the boot 11 and also a heel piece (not shown) that is intended to secure a rear part of the boot to the gliding board. By virtue of the provision of a toepiece 10 as described above, the boot 11 can be released from the binding device in the event of a twisting fall advantageously only by way of the toepiece 10. The heel piece may thus be designed to release the boot 11 only in the event of a forward fall of the skier, and not to release it as a result of twisting. Even in the scope of ski touring, the use of a simple heel piece becomes possible, resulting in lower costs and a lower weight of the binding device with respect to the prior art. This encourages ski touring, for which the overall weight is currently an essential criterion. A backward fall is also covered by the toepiece 10, the jaws then being inclined at an angle that is substantially the same, allowing the boot 11 to come out of the toepiece 10.

Finally, the invention relates to the gliding board as such, which comprises such a toepiece and/or such a binding device. Advantageously, the gliding board constitutes a touring ski.

Finally, it remains possible to provide for the toepiece 10 to be able to release as a result of twisting before one or the other of the jaws has passed the intermediate neutral-point position, thereby advantageously saving the skier from having to pass the neutral point in the opposite direction. 

1. A toepiece of a binding device for securing a boot to a gliding board, comprising two rigid jaws that are mounted so as to pivot about respective substantially horizontal axes that are oriented in a substantially longitudinal direction of the toepiece, comprising a releasing system for automatically releasing the boot as a result of twisting of the boot, associated with tilting of the jaws, said toepiece being configured such that, by tilting of at least one jaw, it takes up: a closed configuration in which retaining elements carried by the jaws can engage with the boot, a releasing configuration for releasing the boot as a result of twisting of the boot, said releasing configuration being different from the closed configuration, in order to automatically free the boot by actuation of the releasing system, a fitting configuration, different from the closed configuration, in particular different from the releasing configuration, and allowing the boot to be fitted in the toepiece between the retaining elements, the releasing system for automatically releasing the boot as a result of twisting of the boot comprising an elastic return means for the jaws in the closed configuration and in the releasing configuration of the toepiece, wherein, in said toepiece, the connection between a jaw and the elastic return means comprises at least one transmission link articulated to the jaw about a first hinge axis that is oriented in the longitudinal direction such that the jaw and its transmission link form a knuckle joint that deforms in the plane corresponding to the transverse direction and vertical direction of the toepiece.
 2. The toepiece as claimed in claim 1, wherein the constituent parts of the elastic return means exhibit movements and/or elastic deformations generally in a plane that is oriented in the longitudinal and transverse directions of the toepiece, during the passage from the closed configuration to the releasing configuration and to the fitting configuration.
 3. The toepiece as claimed in claim 1, wherein the transmission link is articulated to the elastic return means about a second hinge axis that is oriented in the longitudinal direction.
 4. The toepiece as claimed in claim 1, wherein the elastic return means of the releasing system comprises at least one elastically deformable strip.
 5. The toepiece as claimed in claim 1, wherein the elastic return means comprises at least one spring and two lever arms that are articulated and/or elastically deformable.
 6. The toepiece as claimed in claim 5, wherein the lever arms are arranged such that each lever arm makes the connection between one end of said spring that is oriented in the transverse direction and the transmission link connected to one of the jaws.
 7. The toepiece as claimed in claim 5, wherein the elastic return means comprises two transfer links and a tie bar that is oriented and slides in the longitudinal direction of the toepiece so as to stress said spring that is oriented in the longitudinal direction, each transfer link making the connection between the tie rod and one of the lever arms.
 8. The toepiece as claimed in claim 7, wherein the spring is disposed in a fixed housing with respect to a base of the toepiece that is intended to be fixed to the gliding board.
 9. The toepiece as claimed in claim 7, wherein the spring is disposed in a housing that is able to move in the longitudinal direction with respect to a base of the toepiece that is intended to be fixed to the gliding board, such that the housing moves at the same time as the tie bar and the spring during the passage from the closed configuration to the fitting configuration and vice versa, and such that the housing remains fixed with respect to the base during the passage from the closed configuration to the releasing configuration and vice versa.
 10. The toepiece as claimed in claim 5, wherein the elastic return means comprises connecting elements between the two lever arms, allowing the two jaws to move continuously in a synchronous and symmetrical manner with respect to a plane oriented in the longitudinal and vertical directions.
 11. The toepiece as claimed in claim 5, wherein the transmission link connected to the jaw is articulated by its second hinge axis directly to the lever arm by way of a contact between two spherical surfaces that are respectively carried by the transmission link and by the lever arm.
 12. The toepiece as claimed in claim 5, wherein the elastic return means comprises an offsetting link interposed between each lever arm and the transmission link connected to the jaw, the offsetting link being mounted so as to pivot on the lever arm and on the transmission link and optionally on a base of the toepiece that is intended to be fixed to the gliding board.
 13. The toepiece as claimed in claim 1, wherein the angular tilting travel of a jaw between the closed configuration of the toepiece and the releasing configuration of the toepiece is greater than the angular tilting travel thereof between the closed configuration and the fitting configuration.
 14. The toepiece as claimed in claim 1, which comprises an actuating lever that is accessible to the user from outside the toepiece and may take up: a fitting position in which the toepiece is placed in the fitting configuration, a downhill position in which the toepiece is placed in the closed configuration, and an uphill position in which the releasing system is blocked so as to block the toepiece in the closed configuration by preventing any possibility of it passing into the fitting configuration and/or into the releasing configuration.
 15. The toepiece as claimed in claim 14, which comprises a fitting stop that engages with the actuating lever so as to take up an active position in which it forms a support for the boot in the longitudinal direction when the actuating lever is in its fitting position.
 16. The toepiece as claimed in claim 1, wherein the releasing system comprises means for separating the overall tilting travel of the jaw between the closed configuration and the releasing configuration, into first and second angular sectors that are separated by an intermediate neutral-point position of the jaw corresponding to a hard point of inflection of the jaw under the action of the elastic return means.
 17. A binding device for securing a boot to a gliding board, comprising a toepiece as claimed in claim 1 which is intended to secure the front part of the boot, and also a heel piece which is intended to secure a rear part of the boot to the gliding board, the heel piece being designed to release the boot only in the case of a forward fail of the skier, the boot being released from the binding device in the case of a twisting fall only by way of the toepiece.
 18. A gliding board, in particular a touring ski, comprising a toepiece as claimed in claim
 1. 19. A gliding board, in particular a touring ski, comprising a binding device as claimed in claim
 17. 20. A gliding board, in particular a touring ski, comprising a toepiece as claimed in claim 1 and comprising a binding device for securing a boot to a gliding board, comprising a toepiece as claimed in claim 1 which is intended to secure the front part of the boot, and also a heel piece which is intended to secure a rear part of the boot to the gliding board, the heel piece being designed to release the boot only in the case of a forward fall of the skier, the boot being released from the binding device in the case of a twisting fall only by way of the toepiece. 